WiFi Telemetry with Cheap 3$ ESP8266

Hello all,

It's not a new achievement using wifi as Telemetry but this UART to WiFi module has really long range (up to 400 meters), and unbeatable price. Very small form factor (about 2cm x 1.5cm) and light (3 gr). Great for the small sized UAVs. And your Smart Phone or Tablet will become a GCS with no additional hardware. And with module's available GPIOs it's functionality can be increased (PWM, I2C sensors) you can drive LEDs or get sensor data over wifi.

Get firmware from https://github.com/jeelabs/esp-link > this is the stable solution for UART only

Another eriksl's great firmware for ESP8266 https://github.com/eriksl/esp8266-universal-io-bridge > A lot of functions supports pwm display temp sensors but UART bridge not stable, random drop outs

I've been experimenting with new ESP8266 UART to WiFi module and happy to announce you that it can be used as Telemetry module. It should work on all MAVlink devices that uses Serial communication. I tested with ESP-03 and APM 2.6 (3.2) and range is acceptable for Follow Me, or Guided missions. it works reliable enough and its really cheap, start as low as 2,5 $ at several stores (its a 3.3v device you will need a good (about 300ma) power source). I think APM 2.6 users should receive at least a one last bug fix release (several reports indicates 3.2.1 has some issues with altitude calculations), of course you can compile your own verison.

releated fix

https://github.com/diydrones/ardupilot/issues/706

https://github.com/R-Lefebvre/ardupilot/commit/8360b3d

For those who are interested, I can provide APM:Copter 3.2 (not 3.2.1) firmware with the fix. I am happy with it, doing some great auto flights, checking parameters, follow me flights, you can fly your UAV even without RC controller, directly from your wifi enabled GCS.

I have been testing the ESP8266 for telemetry usage, since a couple of months.

The ESP8266 performances are great compared to the price point, and I really think can be a great substitute to the 3DR modems.

Unfortunately I still have several issues to address. Mavlink tends to mess up the module settings for some unknown reason, and the only way to fixit is to re-flash the firmware inside. After the connection is lost, takes a long time to regain connection and this won't be acceptable if used on drones. Last issue is the buffer size and they way the buffer works on the ESP. I'm suspecting that the limited buffer size and the way that is structured is causing some of the issues described before. Something that will really help is the use of CTS/RTS pins on the ESP, unfortunately I did had the time to try them yet.

Anyone with programming skills that want's to help is welcome..

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Comments

Developer

Tom Pittenger July 31, 2015 at 9:17am

I see in this example from TFS that mentions a test application with a baud limit of 1000000

eriksl/esp8266-universal-io-bridge

Universal I/O bridge for the ESP8266, including GPIO, I2C and UART (serial bridge) - eriksl/esp8266-universal-io-bridge
Developer

Tom Pittenger July 31, 2015 at 9:10am

The only baud rate info I see if 57600 or 115200. Since this is a WiFi module it's certainly capable of transmitting more, has anyone tried pushing the Tx speed limits? If there's a buffer problem, as @naish88 says, then high-speed is impossible.
naish July 31, 2015 at 2:48am

I have been testing the ESP8266 for telemetry usage, since a couple of months.

The ESP8266 performances are great compared to the price point, and I really think can be a great substitute to the 3DR modems.

Unfortunately I still have several issues to address. Mavlink tends to mess up the module settings for some unknown reason, and the only way to fixit is to re-flash the firmware inside. After the connection is lost, takes a long time to regain connection and this won't be acceptable if used on drones. Last issue is the buffer size and they way the buffer works on the ESP. I'm suspecting that the limited buffer size and the way that is structured is causing some of the issues described before. Something that will really help is the use of CTS/RTS pins on the ESP, unfortunately I did had the time to try them yet.

Anyone with programming skills that want's to help is welcome..
Petr Hubacek July 30, 2015 at 11:27pm

@Omer thank you for the tip. I was experimenting with TL-WR702N and some other routers and never suceed to make more than 100m with a good signal. I should try to solder an external antena to my mini router.

@Randy a wiki would be very helpful. I wish to find some place where I could find informations to compare like different suff with range / size / price.
Omer July 30, 2015 at 6:14pm

@Petr Hubacek there are routers which run on Linux (openWRT) and very small, with bare pcb it can be even lighter like this one http://www.gl-inet.com/w/?page_id=714 runs at 400 Mhz, and there are other modules which they use same Wireless chip (AR9331) capable to stream video over IP.

With anttena mod:

"Range increased to 400+ meter open air range. Signal quality on IBM laptop was 43% @ 400 meter."
https://revspace.nl/GL-iNet From this link
Developer

Randy July 30, 2015 at 5:31pm

Nice. Thanks for the info!

We really need to add wiki pages for telemetry and video over wifi and also the phone networks (i.e. 3G or 4G). When we do that we should add some of the info from this blog post.
Petr Hubacek July 30, 2015 at 4:06pm

While this board is for data only - I mean the baudrate kbps or Mbps.

What wifi would you propose for IP camera or mobile phone wifi to stream video for 400m range?
Rana July 29, 2015 at 6:59pm

This one is much relevant if 2W above mentioned amplifier is used.

http://www.ebay.in/itm/271913926897?ru=http%3A%2F%2Fwww.ebay.in%2Fs...
Rana July 29, 2015 at 10:28am

Really great efforts by both of you specially in range testing !

Interfacing this module with this one will give almost unlimited range in the air but radio transmitter at 2.4GHz to be avoided in order to keep the interference under control.

http://www.goodluckbuy.com/2-4g-radio-signal-booster-amplifier-for-...
Dez Socks July 29, 2015 at 10:13am

Hi

Bought one at banggood a while back.Done a simple led on/off via wifi. Sitting there ever since.Must pull it out to give this a shot.Running a Apm mini at the moment on 3.1.

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